From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EB034C43441 for ; Wed, 28 Nov 2018 13:07:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A410B20832 for ; Wed, 28 Nov 2018 13:07:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A410B20832 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728504AbeK2AJb (ORCPT ); Wed, 28 Nov 2018 19:09:31 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:59649 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727823AbeK2AJa (ORCPT ); Wed, 28 Nov 2018 19:09:30 -0500 Received: from hsi-kbw-5-158-153-52.hsi19.kabel-badenwuerttemberg.de ([5.158.153.52] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1gRzZE-0005cU-CN; Wed, 28 Nov 2018 14:07:48 +0100 Date: Wed, 28 Nov 2018 14:07:42 +0100 (CET) From: Thomas Gleixner To: Vitaly Kuznetsov cc: Nadav Amit , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , "Michael Kelley (EOSG)" , "kvm@vger.kernel.org" , Paolo Bonzini , =?ISO-8859-2?Q?Radim_Kr=E8m=E1=F8?= , "linux-kernel@vger.kernel.org" , "x86@kernel.org" , Roman Kagan Subject: Re: [PATCH v2 1/4] x86/hyper-v: move synic/stimer control structures definitions to hyperv-tlfs.h In-Reply-To: <87a7ltjxnz.fsf@vitty.brq.redhat.com> Message-ID: References: <20181126154732.23025-1-vkuznets@redhat.com> <20181126154732.23025-2-vkuznets@redhat.com> <20181126200413.GA7852@rkaganb.sw.ru> <87wooyk6na.fsf@vitty.brq.redhat.com> <20181127184835.GA5147@rkaganip.lan> <8A215F49-BB8F-4E93-AC62-EC33B4734F24@gmail.com> <87a7ltjxnz.fsf@vitty.brq.redhat.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="8323329-1590561786-1543410468=:1532" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-1590561786-1543410468=:1532 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT On Wed, 28 Nov 2018, Vitaly Kuznetsov wrote: > Nadav Amit writes: > > > > > On a different note: how come all of the hyper-v structs are not marked > > with the “packed" attribute? > > "packed" should not be needed with proper padding; I vaguely remember > someone (from x86@?) arguing _against_ "packed". Packed needs to be used, when describing fixed format data structures in hardware or other ABIs, so the compiler cannot put alignment holes into them. Using packed for generic data structures might result in suboptimal layouts and prevents layout randomization. Thanks, tglx --8323329-1590561786-1543410468=:1532--